The objective of this investigation is to compare the cardioprotective effects and safety of two cardioplegic solutions, HTK Cardioplegic Solution (Custodiol) and Custodiol-N in patients undergoing cardiopulmonary bypass for coronary artery bypass surgery. The study design is a prospective, double blind, multicenter, randomized, Phase III comparison study intended to demonstrate non-inferiority in surgical outcome between Custodiol and Custodiol-N as determined by CK-MB area under the curve (primary endpoint), catecholamine requirement(cumulative dose) and cardiac Troponin T, occurrence of comorbid events postoperatively (e.g., myocardial infarction).